John p



(No Model.)

J. P. RIDER.

INDIA BUBBBB BALL.

Patented Sept. 22, 1885.

UNrTnn STATES PATENT JOHN P. RIDER, OF FISHKILL, NEV YORK.

INDIA-RUBBER BALL.

WCEICATIOI? forming part of Letters Patent No. 326,788, dated September 22, 1885.

Application filed April 17, 1855. (No model.)

T0 all whmn it may concern:

Be it known that I, JOHN P. RIDER, of Fishkill, Dutchess county, N ew York, have invented a new and useful Improvement in India-Rubber Balls, which improvement is fully set forth in the following specication.

My invention relates to that class of indiarubber balls that are used in playing lawntennis and other similar games. It is very difficult to produce all the qualities in a hollow elastic rubber ball which are desired by experts in lawn-tennis. The balls must all be exactly of a fixed and uniform size and weight. The balls must have hardness, lightness, the proper degree of elasticity, quickness of rebound when struck by the racket or tennis bat, or, in other words, resiliency-that is, a rapid elasticity of a quality similar to that of steel. It must be sufficiently hard and stiff not to flatten against the blow of the racket.

In practical manufacture it has been found very difficult to produce balls that combine all these qualities, because, as rubber goods are ordinarily manufactured, some of these qualities are inconsistent with others, as will be plainly apparent to any expert in the manufacture ofhollow rubber goods. For instance, the ball must be made hard. It would be very easy to produce this quality of hardness by the introduction of numerous adulterants known to this branch of manufacture, but this class of adulterants would destroy the strength and toughness and elasticity of the rubber, and thus destroy the quick action of the ball, which is an absolute essential, as well as its durability. The ball as now ordinarily made is of uniform thickness throughout, the object being that it may be well balanced, and that it may rebound accurately either when struck by the racket or when it strikes the ground; but a satisfactory degree of quickness of rebound has never been obtained in tennisballs as ordinarily manufactured. The tendency is for the ball to hang upon the racket, to momentarily flatten against the face of the comparatively flat surface of the racket when it is struck, and also in a less degree against the ground. The racket itself is composed of highly elastic stringy materials subject to strong tension, and the ball is liable to be struck with the utmost force that the player can impart to the blow.

One of the most important objects to beattained by this invention is a quick rebound, sor that the ball should leave the racket instantly upon being struck, no matter how severe the blow, and without flattening to any perceptible degree, and at the same time that the ball should be sufficiently strong, tough, and durable to endure the severe blows that it receives. Various efforts have been made to overcome these difficulties. The most successful balls in meeting these requirements that have heretofore been made were those in which the seams overlapped. Such balls are made in four pieces of substantially equal size, almost elliptical in form, but coming to a point at each end, and are cut from flat sheets of rubber. The workman joins these four quarters successively into the approximate shape of a hollow sphere, the edges of the pieces slightly overlapping and the ends of each piece meeting at the two poles of the ball. The ball in this condition does not form a perfect sphere. It is then placed into a spherical mold and heated, which causes the rubber to expand and thus receive the shape of the mold. \Vhen it is desired to overlap the seams, this must be done by hand-manipulation. It is comparatively easy to make three of the seams, because the workman can both see and manipulate the inner and outer sides of the seams, but when the last one is joined he can neither see nor manipulate the inner side of the seam, and the result is that it is impossible to lap the lust seam like the other seams with any degree of accuracy and uniformity,and to do it with even an approximate degree of certainty requires highlyskilled labor. The seams thus made stiffen the ball and tend to give it a quicker action, but the balls thus made are of an uneven charater. All the seams cannot be lapped alike, and the ball is not equally resisting or of an even character' at all points along its seams, and the balls vary greatly in their action and rebound.

My invention accomplishes the desired results, and at the same time is more economical and simpler, and the balls are more durable, reliable, and uniform, and do not require the employment of highly-skilled labor to make them.

My invention consists in the insertion inthe interior of the ball of four strips of rubber or gutta-percha'placed equidistant, or substantially so, from each other, and preferably at right angles to the line of the mold-seam, and running from end to end of each quarter of the ball along the center of each quarter on the inner side. The number of the strips may of course be varied, as well as their position. These lines, however, in order to properly balance the ball, should join at opposite poles of the ball. Strips about three-eighths of an inch in width and three-sixteenths to one,- quarter of an inch in thickness have been found to answer the purpose very well. I attach the re-enforcing ribs to the quarters of rubber before they are put together and the ball formed, There is no difficulty in doing this with accuracy, and the ordinary workman can so place the ribs upon the'quarters that the balls when put together will be uni form, and thus the uncertainty of result which attended the best method of manufacture formerly known is avoided, and the eXpenseis reduced. y

In making the ball pursuant to my invention the seams are preferably not lapped, but are what is known as butt-seams, the latter seams being made with much greater facility and accuracy than are the lapped seams.

In the accompanying drawings, Figure l is a view of the outside of a b'all constructed in accordance with the invention, and Fig. 2 a cross-section on line x x.-

Ihe ball is made up of four quarters in the usual way, the edges being brought together forming what is known as a butt-joint. The

lines a indicate these joints. Before the quarters are brought together the elastic re-enforcing strips b are applied, preferably along thel center line of each quarter, though obviously their exact location is not material. The ends of these strips meet at the opposite poles, AB,of the ball. A ball constructed in this way, and otherwise properly made in the manner well known to manufacturers of rubber balls, has been found to possess in a high degree all the qualities which are desirable in a lawn-tennis ball, especially the qualities of quickness and accuracy in responding to the blow given it by the racket. The elasticity which is required is peculiar. A very high degree of elasticity is not required as much as quickness `of action, and this result is obtained by my invention.

What I claim, and desire to secure by Letters Patent, is-

1. As a new article of manufacture, a hollow elastic ball made of india-rubber, with re-enforcing elasticstrips on its inner surface, substantially as described. 4 4

2. A hollow lawn-tennis ball composed of an elastic material, the innersurface of which is re-enforeed by elastic strips, substantially as described.

In testimony whereof I have signed this specieation in the presence of two subscribing witnesses.

JNO. P. RIDER.

Witnesses:

JAMEs F. HoRAN, RUFUs A. BROWN. 

